“Falsehood is invariably the child of fear in one form or another.” -Aleister Crowley
The adage of the boy who cried wolf is important and well-known, however, the Netziv has a slightly different take on it.
The nation of Israel has escaped from the centuries of Egyptian slavery. God parted the sea for them, allowing them to miraculously walk on dry land and see the Egyptian military annihilated. The Israelites walk through the desert, find a stream of bitter waters and then Moses is directed to put nearby trees in the water, thereby sweetening the stream and providing water to the entire nation.
However, a chapter later, the Israelites find themselves again without water, but this time the interplay is different. They complain that they have no water. Moses is not impressed by their complaint. Only after they complain does the text say that the people were thirsty. The Netziv on the verse (Exodus 17:3) explains that though they lacked water they complained before they became thirsty. And so, the false complaint of thirst came true. He then expands that whoever fakes a complaint, eventually it will become true.
A person who claims to not have money, will eventually see that fulfilled. A person who lies about his inability to do something, eventually will lose that ability. A boy who cries wolf, not only will he not be believed, but eventually will have his false statement made true and bring a wolf upon himself.
May we be very careful about our claims and statements, lest they become true.
To truth-speakers. May only blessings be your reward.